An internal electron donor for olefin polymerization, a procatalyst component, a catalyst

Abstract

This invention discloses an internal electron donor for olefin polymerization, a main catalyst component, and a catalyst. The internal electron donor has the following structure: wherein R1 and R2 are the same or different, and each is independently selected from C2 to C3. 20 Straight-chain or branched alkyl groups, C3-C4 20 cycloalkyl, C6-C 20 aryl, C7~C 20 Aryl alkyl group; R3 and R4 may be the same or different, and each is independently selected from hydrogen atoms, C1 to C4. 20 Straight-chain or branched alkyl groups, C3-C 20 cycloalkyl, C6-C 20 aryl, C7~C 20 Aryl groups. This novel internal electron donor, a triether compound with a tetrahydrofuran backbone and a specific structure, can simultaneously improve the catalytic activity of the catalyst and the isotacticity of polypropylene.

Description

Technical Field

[0001] This invention belongs to the field of olefin polymerization catalyst technology, specifically relating to an internal electron donor, main catalyst component, and catalyst for olefin polymerization. Background Technology

[0002] Among polyolefin resins, polypropylene is one of the most in-demand resins in the world market due to its high-performance properties, such as stiffness, impact resistance, transparency, recyclability, light weight, corrosion resistance, high melting temperature, good processability, and low production costs. Polypropylene has a variety of applications in daily life, including packaging, toys, piping, and specialized applications in aircraft and automobiles.

[0003] Ziegler-Natta catalysts are the main catalysts used in the industrial production of polypropylene due to their high catalytic activity, good economics, and relatively mature technology. The internal electron donor in the Ziegler-Natta catalyst system can be directly bonded to the magnesium chloride support, significantly impacting the catalyst activity and the performance of the polypropylene product. Currently, research on internal electron donors both domestically and internationally mainly focuses on traditional fatty acid esters and aromatic acid esters, diethers and succinates, and glycol esters. However, these internal electron donors all have certain problems in practical applications. Internal electron donor families often need to complement each other, utilizing the function of the internal electron donor to adjust the catalyst properties.

[0004] Therefore, the development of novel internal electron donors is an important research area for Ziegler-Natta polypropylene catalyst systems. To improve the overall performance of polypropylene, finding novel internal electron donors with more refined properties has become a primary research goal.

[0005] Regarding the improvement of catalyst performance and thus the enhancement of polypropylene performance by internal electron donors in Ziegler-Natta catalysts, Chinese patent CN101195668B discloses a succinate-based internal electron donor containing a specific structure, which has the following structure:

[0006]

[0007] In the formula, the substituents R1, R2, R3, R4, R5, R6, R7, and R8 may be the same or different, and are selected from H, halogen atoms, C1 to C2. 20 Straight-chain or branched alkyl groups, C3-C4 20 cycloalkyl, C6-C 20 aryl or C7~C 20 Aryl alkyl group; wherein substituents R9, R 10 Same or different, selected from C1 to C 20 Straight-chain or branched alkyl groups, C3-C4 20 cycloalkyl, C6-C20 aryl or C7~C 20 The aralkyl group. Because the internal electron donor uses a novel succinate compound with a large substituent group and spirocyclic structure on the molecular backbone, the resulting main catalyst has high catalytic activity when used to catalyze propylene polymerization. At the same time, the product polypropylene has high stereoregularity. With the addition of a co-catalyst, polypropylene with different isotacticities can be obtained.

[0008] Chinese patent CN116948065A discloses a bisphosphine compound containing a thiophene structure as an internal electron donor, the internal electron donor compound having the following structure:

[0009]

[0010] In the formula, R1, R2, R3, and R4 may be the same or different, and are selected from hydrogen atoms, C1 to C4 atoms. 20 Straight-chain or branched alkyl groups, C3-C4 20 cycloalkyl, C6-C 20 aryl, C7~C 20 Aryl groups and C7-C 20 The alkoxyaryl group; R1, R2, R3 and R4 are preferably C1 to C4. 10 Straight-chain or branched alkyl groups, C3-C4 10 cycloalkyl, C6-C 10 aryl, C7~C 10 Aryl groups or C7-C 10 The catalyst contains alkoxyaryl groups. Because the internal electron donor is a bisphosphine compound with a thiophene structure, the lone pairs of electrons from its phosphorus and sulfur atoms can stabilize the central titanium metal, resulting in high catalyst activity during propylene polymerization. Furthermore, the phosphorus and sulfur atoms of the internal electron donor provide two different chemical environments, which, combined with the spatial structure provided by the thiophene skeleton, result in a polymer with good isotacticity and a broad molecular weight distribution when used in propylene polymerization.

[0011] Chinese patent CN117126310A discloses a 2,3-dihalosubstituted maleate type internal electron donor, which has the following structure:

[0012]

[0013] In the formula, X 1 and X 2 Same or different, independently selected from one of fluorine, chlorine, bromine and iodine; R 1 and R 2 They are either the same or different, and are selected independently from C1 to C2. 12The alkyl group, more preferably a C3-C5 alkyl group, is used. Because the 2,3-dihalosubstituted maleate acts as an internal electron donor, the polypropylene catalyst achieves ultra-high activity, exhibiting superior performance compared to 2,3-dialkyl-substituted or 2,3-diaryl-substituted maleates.

[0014] The article "Propylene Polymerization over MgCl2-Supported Ziegler–Natta Catalysts Containing Tri-Ether as the Internal Donor" studies the synthesis of a novel triether compound as an internal electron donor for MgCl2-supported Ziegler–Natta catalysts and characterizes it.

[0015] The structure of the triether compound is as follows:

[0016]

[0017] A MgCl2-supported Ziegler–Natta catalyst was synthesized using TiCl4, MgCl2 adducts, and triether compounds as raw materials. The results showed that the isotacticity of polypropylene was significantly improved, but the catalytic activity of the catalyst was not significantly enhanced.

[0018] US Patent US2022 / 0411543A1 designs a 2,2-bis(tetrahydrofuranyl)methane compound involving optional unit substitution, with the following structure:

[0019]

[0020] R1 is selected from H and C. 1-7 The straight-chain or branched alkyl group, CH2OR2, and oxygen-containing heterocycles; while R2 is selected from C 1-8 It is a straight-chain, branched, or cyclic alkyl group. Preferably, R1 is selected from H, C. 1-5 The linear or branched alkyl group and 2-tetrahydrofuranyl group. More preferably, R1 is selected from H, C 1-3 The compound is composed of alkyl and 2-tetrahydrofuranyl groups. Most preferably, R1 is selected from H, methyl, and 2-tetrahydrofuranyl groups. Using this compound as an internal electron donor in a Ziegler-Natta catalyst improves the catalytic activity of the catalyst and produces a polymer with a broad molecular weight distribution, but the polymer exhibits poor isotacticity.

[0021] Currently, the most effective way to improve both the catalytic activity of the catalyst and the isotacticity of polypropylene is to design a novel internal electron donor that meets the requirements. Summary of the Invention

[0022] The purpose of this invention is to provide an internal electron donor for olefin polymerization. This internal electron donor is a novel triether-based internal electron donor compound with a tetrahydrofuran backbone and a specific structure, which can simultaneously improve the catalytic activity of the catalyst and the isotacticity of polypropylene.

[0023] Another objective of this invention is to provide a main catalyst component for olefin polymerization.

[0024] Another objective of this invention is to provide a catalyst for olefin polymerization.

[0025] To achieve the above objectives, the present invention provides an internal electron donor for olefin polymerization, having the following structure:

[0026]

[0027] Among them, R1 and R2 may be the same or different, and each is independently selected from C2 to C3. 20 Straight-chain or branched alkyl groups, C3-C4 20 cycloalkyl, C6-C 20 aryl, C7~C 20 Aryl alkyl group; R3 and R4 may be the same or different, and each is independently selected from hydrogen atoms, C1 to C4. 20 Straight-chain or branched alkyl groups, C3-C4 20 cycloalkyl, C6-C 20 aryl, C7~C 20 Aryl groups.

[0028] The internal electron donors for olefin polymerization described in this invention, R1 and R2, may be the same or different, and each is independently selected from C2 to C3. 10 Straight-chain or branched alkyl groups, C3-C4 12 cycloalkyl, C6-C 10 aryl, C7~C 10 Aryl alkyl group; R3 and R4 are the same, selected from hydrogen atoms, C1 to C2. 10 Straight-chain or branched alkyl groups, C3-C4 12 cycloalkyl, C6-C 10 aryl, C7~C 10 Aryl groups.

[0029] The internal electron donor for olefin polymerization described in this invention is selected from 3,4-diethoxytetrahydrofuran, 3,4-di-n-propoxytetrahydrofuran, 3,4-diisopropoxytetrahydrofuran, 3,4-di-n-butoxytetrahydrofuran, 3,4-diisobutoxytetrahydrofuran, 3,4-di-n-pentoxytetrahydrofuran, 3,4-dicyclopentoxytetrahydrofuran, 3,4-di-n-hexyloxytetrahydrofuran, 3,4-dicyclohexyloxytetrahydrofuran, 3,4-diphenoxytetrahydrofuran, 3,4-bis(p-tolyloxy)tetrahydrofuran, 3,4-bis(m-tolyloxy)tetrahydrofuran, 3,4-bis(o-tolyloxy)tetrahydrofuran, 2-methyl-3,4-diethoxytetrahydrofuran, 2-methyl-3,4-di-n-propoxytetrahydrofuran, and 2-methyl-3,4-di-n-propoxytetrahydrofuran. Furan, 2-methyl-3,4-diisopropoxytetrahydrofuran, 2-methyl-3,4-di-n-butoxytetrahydrofuran, 2-methyl-3,4-diisobutoxytetrahydrofuran, 2-methyl-3,4-di-n-pentoxytetrahydrofuran, 2-methyl-3,4-dicyclopentoxytetrahydrofuran, 2-methyl-3,4-di-n-hexyloxytetrahydrofuran, 2-methyl-3,4-dicyclohexyloxytetrahydrofuran, 2-methyl-3,4-diphenoxytetrahydrofuran, 2-methyl-3,4-bis(p-tolyloxy)tetrahydrofuran, 2-methyl-3,4-bis(m-tolyloxy)tetrahydrofuran, 2-methyl-3,4-bis(o-tolyloxy)tetrahydrofuran, 2-ethyl-3,4-diethoxytetrahydrofuran, 2-ethyl-3,4-di-n-propoxytetrahydrofuran 2-Ethyl-3,4-diisopropoxytetrahydrofuran, 2-Ethyl-3,4-di-n-butoxytetrahydrofuran, 2-Ethyl-3,4-diisobutoxytetrahydrofuran, 2-Ethyl-3,4-di-n-pentoxytetrahydrofuran, 2-Ethyl-3,4-dicyclopentoxytetrahydrofuran, 2-Ethyl-3,4-di-n-hexyloxytetrahydrofuran, 2-Ethyl-3,4-dicyclohexyloxytetrahydrofuran, 2-Ethyl-3,4-diphenoxytetrahydrofuran, 2-Ethyl-3,4-bis(p-tolyloxy)tetrahydrofuran, 2-Ethyl-3,4-bis(m-tolyloxy)tetrahydrofuran, 2-Ethyl-3,4-bis(o-tolyloxy)tetrahydrofuran, 2-isopropyl-3,4-diethoxytetrahydrofuran, 2-isopropyl- 3,4-Di-n-propoxytetrahydrofuran, 2-Isopropyl-3,4-Diisopropoxytetrahydrofuran, 2-Isopropyl-3,4-Di-n-Butoxytetrahydrofuran, 2-Isopropyl-3,4-Diisobutoxytetrahydrofuran, 2-Isopropyl-3,4-Di-n-pentoxytetrahydrofuran, 2-Isopropyl-3,4-Dicyclopentoxytetrahydrofuran, 2-Isopropyl-3,4-Di-n-Hexoxytetrahydrofuran, 2-Isopropyl-3,4-Dicyclohexyloxytetrahydrofuran, 2-Isopropyl-3,4-Diphenoxytetrahydrofuran, 2-Isopropyl-3,4-bis(p-tolyloxy)tetrahydrofuran, 2-Isopropyl-3,4-bis(m-tolyloxy)tetrahydrofuran, 2-Isopropyl-3,4-bis(o-tolyloxy)tetrahydrofuran, 2-n-Butyl-3,4-Diethoxytetrahydrofuran, 2-n-butyl-3,4-di-n-propoxytetrahydrofuran, 2-n-butyl-3,4-diisopropoxytetrahydrofuran, 2-n-butyl-3,4-di-n-butoxytetrahydrofuran, 2-n-butyl-3,4-diisobutoxytetrahydrofuran, 2-n-butyl-3,4-di-n-pentoxytetrahydrofuran, 2-n-butyl-3,4-dicyclopentoxytetrahydrofuran, 2-n-butyl-3,4-di-hexyloxytetrahydrofuran, 2-n-butyl-3,4-dicyclohexyloxytetrahydrofuran, 2-n-butyl-3,4-diphenoxytetrahydrofuran, 2-n-butyl-3,4-bis(p-tolyloxy)tetrahydrofuran, 2-n-butyl-3,4-bis(m-tolyloxy)tetrahydrofuran, 2-n-butyl-3,4-bis(p-tolyloxy)tetrahydrofuran (o-Tolyloxy)tetrahydrofuran, 2-phenyl-3,4-diethoxytetrahydrofuran, 2-phenyl-3,4-di-n-propoxytetrahydrofuran, 2-phenyl-3,4-diisopropoxytetrahydrofuran, 2-phenyl-3,4-di-n-butoxytetrahydrofuran, 2-phenyl-3,4-diisobutoxytetrahydrofuran, 2-phenyl-3,4-di-n-pentoxytetrahydrofuran, 2-phenyl-3,4-dicyclopentoxytetrahydrofuran, 2-phenyl-3,4-di-n-hexyloxytetrahydrofuran, 2-phenyl-3,4-dicyclohexyloxytetrahydrofuran, 2-phenyl-3,4-diphenoxytetrahydrofuran, 2-phenyl-3,4-bis(p-tolyloxy)tetrahydrofuran, 2-phenyl-3,4-bis(m-tolyloxy)tetrahydrofuran, 2-phenyl -3,4-bis(o-tolyloxy)tetrahydrofuran, 2,5-dimethyl-3,4-diethoxytetrahydrofuran, 2,5-dimethyl-3,4-di-n-propoxytetrahydrofuran, 2,5-dimethyl-3,4-diisopropoxytetrahydrofuran, 2,5-dimethyl-3,4-di-n-butoxytetrahydrofuran, 2,5-dimethyl-3,4-diisobutoxytetrahydrofuran, 2,5-dimethyl-3,4-di-n-pentoxytetrahydrofuran, 2,5-dimethyl-3,4-dicyclopentoxytetrahydrofuran, 2,5-dimethyl-3,4-di-n-hexyloxytetrahydrofuran, 2,5-dimethyl-3,4-dicyclohexyloxytetrahydrofuran, 2,5-dimethyl-3,4-diphenoxytetrahydrofuran, 2,5-dimethyl-3,4-diphenyloxytetrahydrofuran, 2,5-dimethyl-3,4- Bis(p-tolyloxy)tetrahydrofuran, 2,5-dimethyl-3,4-bis(m-tolyloxy)tetrahydrofuran, 2,5-dimethyl-3,4-bis(o-tolyloxy)tetrahydrofuran, 2,5-diethyl-3,4-diethoxytetrahydrofuran, 2,5-diethyl-3,4-di-n-propoxytetrahydrofuran, 2,5-diethyl-3,4-diisopropoxytetrahydrofuran, 2,5-diethyl-3,4-di-n-butoxytetrahydrofuran, 2,5-diethyl-3,4-di-n-butoxytetrahydrofuran, 2,5-diethyl-3,4-di-n-pentoxytetrahydrofuran, 2,5-diethyl-3,4-dicyclopentoxytetrahydrofuran, 2,5-diethyl-3,4-di-n-hexyloxytetrahydrofuran, 2,5-diethyl-3,4-Dicyclohexyloxytetrahydrofuran, 2,5-diethyl-3,4-diphenoxytetrahydrofuran, 2,5-diethyl-3,4-bis(p-tolyloxy)tetrahydrofuran, 2,5-diethyl-3,4-bis(m-tolyloxy)tetrahydrofuran, 2,5-diethyl-3,4-bis(o-tolyloxy)tetrahydrofuran, 2,5-diisopropyl-3,4-diethoxytetrahydrofuran, 2,5-diisopropyl-3,4-di-n-propoxytetrahydrofuran, 2,5-diisopropyl-3,4-diisopropoxytetrahydrofuran, 2, 5-Diisopropyl-3,4-Di-n-Butoxytetrahydrofuran, 2,5-Diisopropyl-3,4-Diisobutoxytetrahydrofuran, 2,5-Diisopropyl-3,4-Di-n-Pentoxytetrahydrofuran, 2,5-Diisopropyl-3,4-Dicyclopentoxytetrahydrofuran, 2,5-Diisopropyl-3,4-Di-n-Hexoxytetrahydrofuran, 2,5-Diisopropyl-3,4-Dicyclohexoxytetrahydrofuran, 2,5-Diisopropyl-3,4-Diphenoxytetrahydrofuran, 2,5-Diisopropyl-3,4-Dibis(p-Tolyloxy) Tetrahydrofuran, 2,5-diisopropyl-3,4-bis(m-tolyloxy)tetrahydrofuran, 2,5-diisopropyl-3,4-bis(o-tolyloxy)tetrahydrofuran, 2,5-diphenyl-3,4-diethoxytetrahydrofuran, 2,5-diphenyl-3,4-di-n-propoxytetrahydrofuran, 2,5-diphenyl-3,4-diisopropoxytetrahydrofuran, 2,5-diphenyl-3,4-di-n-butoxytetrahydrofuran, 2,5-diphenyl-3,4-diisobutoxytetrahydrofuran, 2,5-diphenyl-3,4-diisobutoxytetrahydrofuran, 2,5-diphenyl-3,4- One or more of the following: di-n-pentoxytetrahydrofuran, 2,5-diphenyl-3,4-dicyclopentoxytetrahydrofuran, 2,5-diphenyl-3,4-di-n-hexyloxytetrahydrofuran, 2,5-diphenyl-3,4-dicyclohexyloxytetrahydrofuran, 2,5-diphenyl-3,4-diphenoxytetrahydrofuran, 2,5-diphenyl-3,4-bis(p-tolyloxy)tetrahydrofuran, 2,5-diphenyl-3,4-bis(m-tolyloxy)tetrahydrofuran, and 2,5-diphenyl-3,4-bis(o-tolyloxy)tetrahydrofuran.

[0030] To achieve the above objectives, the present invention also provides a main catalyst component for olefin polymerization, comprising the aforementioned internal electron donor, Mg, Ti, and Cl.

[0031] The olefin polymerization main catalyst component of the present invention comprises an internal electron donor content of 1-15 wt%, a Mg content of 12-25 wt%, a Ti content of 1-15 wt%, and a Cl content of 45-60 wt%.

[0032] To achieve the above objectives, the present invention also provides an olefin polymerization catalyst, comprising the main catalyst component, co-catalyst, and external electron donor described above.

[0033] The olefin polymerization catalyst of the present invention comprises an aluminum-containing compound as the co-catalyst and a silicon-containing compound as the external electron donor. The main catalyst component is calculated based on Ti, the co-catalyst based on Al, and the external electron donor based on Si. The molar ratio of the main catalyst component, the co-catalyst, and the external electron donor is 1:100-1000:100-500.

[0034] The olefin polymerization catalyst of the present invention comprises a co-catalyst selected from one or more of trimethylaluminum, triethylaluminum, and triisobutylaluminum.

[0035] The olefin polymerization catalyst of the present invention has an external electron donor selected from one or more of methylcyclohexyldimethoxysilane, dicyclopentyldimethoxysilane, diisopropyldimethoxysilane, and diphenyldimethoxysilane.

[0036] Beneficial effects of this invention:

[0037] (1) When the triether compound containing a tetrahydrofuran structure provided by this invention is used as an internal electron donor component in a propylene polymerization catalyst, it has a special tetrahydrofuran structure compared with ordinary ether compounds, which has higher stability, provides a spatial structure, and has a larger electron cloud density. It has a stronger coordination effect with magnesium chloride support and is less likely to be replaced by co-catalysts, thus facilitating the formation of isotactic active centers. (2) When the triether compound containing a tetrahydrofuran structure provided by this invention is used as an internal electron donor component in a propylene polymerization catalyst, the oxygen atoms of its three ether bonds coordinate with magnesium atoms, affecting the Ti active center through the O→Mg→Cl→Ti electronic effect channel. Compared with traditional diether compounds, it has one more ether bond, and the lone pair electrons provided by the oxygen atoms can more firmly stabilize the central metal Ti, thereby optimizing the catalytic activity of the catalyst.

[0038] (3) When the novel internal electron donor of the triether with a special structure provided by the present invention is used for propylene polymerization, the catalyst exhibits high activity and also improves the isotacticity of polypropylene.

[0039] (4) The novel internal electron donor compounds containing tetrahydrofuran structure triethers provided by this invention have the characteristics of low cost, few synthesis steps and high yield in organic synthesis. Detailed Implementation

[0040] The present invention will now be described in detail through embodiments. It should be noted that the following embodiments are only for further illustration of the present invention and should not be construed as limiting the scope of protection of the present invention. Those skilled in the art can make some non-essential improvements and adjustments to the present invention based on the above description.

[0041] Test methods and standards:

[0042] Polypropylene isotacticity: The isotacticity was determined using the heptane extraction method (boiling heptane extraction for 6 hours). 5g of dry polypropylene powder was placed in an extractor and extracted with boiling heptane for 6 hours. The residue was then dried to a constant weight, and the ratio of the obtained polypropylene powder weight (g) to 5g was calculated. The results are shown in Table 1.

[0043] Example 1

[0044] (1) Synthesis of internal electron donors

[0045] Step 1: Under a nitrogen atmosphere, 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ, 2 mmol, 0.4 g) was added dropwise to 2,5-dimethyltetrahydrofuran (0.16 mol, 16 g), and the temperature was maintained at around 0 °C. The mixture was stirred for 30 min, then stirred at room temperature for 6 h. The mixture was washed three times with hexane, and then the hexane was removed. Finally, a colorless and transparent liquid, 2,5-dimethyl-2,5-dihydrofuran (12 g, 76.4% yield), was obtained.

[0046] Step 2: In a nitrogen atmosphere, anhydrous aluminum chloride (3g) was added to 30% hydrogen peroxide (24g), and stirred at room temperature for 30min. Then, 2,5-dimethyl-2,5-dihydrofuran (10g) was added, and the mixture was heated in an oil bath to 65℃ and stirred for 24h. After cooling to room temperature, the mixture was filtered to remove impurities, and finally, a pale yellow liquid, 2,5-dimethyl-3,4-tetrahydrofuran diol (9.3g, 69.1% yield), was obtained.

[0047] Step 3: Under a nitrogen atmosphere, anhydrous potassium carbonate (0.03 mol, 4 g), 2,5-dimethyl-3,4-tetrahydrofurandiol (68 mmol, 9 g), and bromobenzene (136 mmol, 21.35 g) were added to 100 ml of acetone. The mixture was heated to 20 °C and reacted for 2 h. After washing and removing impurities, an orange-yellow liquid, 2,5-dimethyl-3,4-diphenoxytetrahydrofuran (14.3 g, 74.0% yield), was finally obtained. 1 H NMR (500MHz, DMSO-d6) δ7.28–7.21 (m, 4H), 6.99–6.90 (m, 6H), 4.66 (ddt, J=2.1, 1.4, 0.7Hz, 2H), 4.05–3.98 (m, 2H) 1.20–1.14 (m, 6H).

[0048] (2) Catalyst preparation

[0049] Under anhydrous and oxygen-free conditions, 121.4 ml of titanium tetrachloride was cooled to approximately -20°C, and 5 g of spherical magnesium chloride alcohol granules (molar ratio of alcohol to magnesium chloride was 2.85:1, molecular formula MgCl2·2.85CH3CH2OH) were added. The mixture was allowed to react at approximately -20°C for 1 h, then the temperature was gradually increased to 60°C, and 1.05 g of 2,5-dimethyl-3,4-diphenoxytetrahydrofuran was added. The temperature was further increased to 110°C and reacted for 2 h. After filtration, another 121.4 ml of titanium tetrachloride was added, and the temperature was increased to 120°C and reacted for 2 h. After filtration, the mixture was washed four times with hexane at 50°C and twice with hexane at room temperature. Finally, after vacuum drying, a polypropylene main catalyst was obtained. The main catalyst contained 4.2% internal electron donor, 25.0% Mg, 9.8% Ti, and 57.4% Cl.

[0050] (3) Propylene polymerization

[0051] The stainless steel reactor was vacuum dried and purged with nitrogen several times. Then, 2 kg of propylene, 0.8 ml of triethylaluminum (co-catalyst), 1.3 ml of methylcyclohexyldimethoxysilane (external electron donor), 30 mg of the main catalyst prepared in (2), and 0.3 g of hydrogen were added. The mixture was heated to 70 °C and reacted for 1 h. The mixture was then cooled to room temperature and depressurized to obtain polypropylene powder. After the polypropylene powder was dried, it was weighed, and the catalyst activity was calculated. The results are shown in Table 1.

[0052] Example 2

[0053] Repeat Example 1, but replace the bromobenzene (21.35 g) in step 3 of (1) with bromoethane (14.82 g) to obtain 2,5-dimethyl-3,4-diethoxytetrahydrofuran (0.69 g). 1 ¹H NMR (500MHz, DMSO-d6) δ 3.94 (s, 2H), 3.79 (s, 2H), 3.59 (d, J = 12.4Hz, 2H), 3.51 (d, J = 12.5Hz, 2H), 1.24-1.23 (d, J = 7.1Hz, 6H), 1.23-1.21 (d, J = 7.2Hz, 6H); 2,5-dimethyl-3,4-diphenoxytetrahydrofuran (1.05g) in (2) was replaced with 2,5-dimethyl-3,4-diethoxytetrahydrofuran (0.69g); In the main catalyst, the content of internal electron donor was 1.0%, the content of Mg was 13.6%, the content of Ti was 1.9%, and the content of Cl was 46.8%. Replace 0.8 ml of triethylaluminum in (3) with 0.5 ml of triethylaluminum, and replace 1.3 ml of methylcyclohexyldimethoxysilane with 0.5 ml of methylcyclohexyldimethoxysilane.

[0054] Example 3

[0055] Repeat Example 1, but replace the bromobenzene (21.35 g) in step 3 of (1) with n-propyl bromide (16.73 g) to obtain 2,5-dimethyl-3,4-di-n-propoxytetrahydrofuran (0.79 g). 1 ¹H NMR (500MHz, DMSO-d6) δ 3.94 (s, 2H), 3.79 (s, 2H), 3.57 (d, J = 12.5Hz, 2H), 3.49 (d, J = 12.5Hz, 2H), 1.56 (d, J = 15.2Hz, 4H), 1.24 (s, 6H), 0.93 (s, 6H)); 2,5-dimethyl-3,4-diphenoxytetrahydrofuran (1. 0.5g) was replaced with 2,5-dimethyl-3,4-di-n-propoxytetrahydrofuran (0.79g). In the main catalyst, the content of internal electron donor was 15.0%, the content of Mg was 12.9%, the content of Ti was 15.0%, and the content of Cl was 50.4%. In (3), 0.8ml of triethylaluminum was replaced with 6.3ml of triethylaluminum, and 1.3ml of methylcyclohexyldimethoxysilane was replaced with 9.8ml of methylcyclohexyldimethoxysilane.

[0056] Example 4

[0057] Repeat Example 1, but replace 2,5-dimethyltetrahydrofuran (16g) in step 1 of (1) with tetrahydrofuran (11.5g); replace 2,5-dimethyl-2,5-dihydrofuran (10g) in step 2 of (1) with 2,5-dihydrofuran (7.14g); replace 2,5-dimethyl-3,4-tetrahydrofurandiol (68mmol, 9g) and bromobenzene (136mmol, 21.35g) in step 3 with 3,4-tetrahydrofurandiol (7.08g) and bromoethane (14.82g) to obtain 3,4-diethoxytetrahydrofuran (0.59g). 1 HNMR (500MHz, DMSO-d6) δ 4.12 (s, 2H), 3.72 (d, J = 8.1Hz, 2H), 3.61–3.50 (m, 6H), 1.20 (s, 6H); 2,5-dimethyl-3,4-diphenoxytetrahydrofuran (1.05g) in (2) was replaced with 3,4-diethoxytetrahydrofuran (0.59g). In the main catalyst, the content of internal electron donor was 2.6%, the content of Mg was 17.2%, the content of Ti was 1.0%, and the content of Cl was 52.3%; 0.8ml of triethylaluminum in (3) was replaced with 0.5ml of trimethylaluminum, and 1.3ml of methylcyclohexyldimethoxysilane was replaced with 0.4ml of dicyclopentyldimethoxysilane.

[0058] Example 5

[0059] Repeat Example 4, but replace the bromoethane (14.82 g) in step 3 of (1) with n-propyl bromide (16.73 g) to obtain 3,4-di-n-propoxytetrahydrofuran (0.69 g). 1 ¹H NMR (500MHz, DMSO-d⁶) δ 4.18 (s, 2H), 3.73 (d, J = 8.1Hz, 2H), 3.60 (d, J = 12.4Hz, 2H), 3.57–3.51 (m, 4H), 1.58 (d, J = 12.5Hz, 4H), 0.93 (s, 6H); 3,4-diethoxytetrahydrofuran (0.59) in (2) g) was replaced with 3,4-di-n-propoxytetrahydrofuran (0.69 g). In the main catalyst, the content of internal electron donor was 7.5%, the content of Mg was 18.7%, the content of Ti was 12.4%, and the content of Cl was 60.0%. In (3), 0.5 ml of trimethylaluminum was replaced with 3.5 ml of trimethylaluminum, and 1.3 ml of dicyclopentyldimethoxysilane was replaced with 1.7 ml of diisopropyldimethoxysilane.

[0060] Example 6

[0061] Repeat Example 4, but replace bromoethane (14.82 g) in step 3 of (1) with bromobenzene (21.35 g) to obtain 3,4-diphenoxytetrahydrofuran (0.94 g). 1 ¹H NMR (500MHz, DMSO-d⁶) δ 7.32–7.24 (m, 4H), 6.99 (tt, J = 7.5, 2.0Hz, 2H), 6.97–6.91 (m, 4H), 4.78 (s, 2H), 3.93 (d, J = 7.9Hz, 2H), 3.85 (d, J = 7.9Hz, 2H); 3,4-diethoxytetrahydrofuran in (2) (0.59g) was replaced with 3,4-diphenoxytetrahydrofuran (0.94g). In the main catalyst, the content of internal electron donor was 2.9%, the content of Mg was 12.0%, the content of Ti was 3.8%, and the content of Cl was 45.0%. In (3), 0.5ml of trimethylaluminum was replaced with 2.7ml of triisobutylaluminum, and 1.3ml of dicyclopentyldimethoxysilane was replaced with 1.6ml of diphenyldimethoxysilane.

[0062] Comparative Example 1

[0063] Repeat steps (2) and (3) of Example 1, but replace 2,5-dimethyl-3,4-diphenoxytetrahydrofuran (1.05 g) in (2) with 1-methoxy-2,2-bis(methoxymethyl)butane (0.65 g). The specific synthesis method of 1-methoxy-2,2-bis(methoxymethyl)butane is as follows: First, in a dry nitrogen atmosphere, dissolve 0.09 mol of NaH in 33 ml of tetrahydrofuran, and lower the temperature. At 0°C, a solution of 1,1,1-tris(hydroxymethyl)propane (prepared using 0.02 mol of 1,1,1-tris(hydroxymethyl)propane and 33 ml of tetrahydrofuran) was added using a dropping funnel and stirred at room temperature for 1 h. Then, the mixture was cooled to 0°C, 0.12 mol of iodomethane was added, the temperature was raised to 35°C and stirred for 2 h. Finally, after washing, extraction and drying, 1-methoxy-2,2-bis(methoxymethyl)butane was obtained. 1 H NMR (500MHz, DMSO-d6) δ3.56 (d, J=12.4Hz, 3H), 3.44 (d, J=12.3Hz, 3H), 3.33 (s, 9H), 1.36 (q, 2H), 0.83 (t, 3H).

[0064] Comparative Example 2

[0065] Repeat (2) and (3) in Example 1, but replace 2,5-dimethyl-3,4-diphenoxytetrahydrofuran (1.05 g) in (2) with 2,5-bis(1-(furan-2-yl)ethyl)furan (0.94 g). The specific synthesis method of 2,5-bis(1-(furan-2-yl)ethyl)furan is as follows: First, mix 85 ml of ethanol and 50 ml of furan, then add 60 g of acetaldehyde; then, stir at room temperature for 20 h; finally, wash, extract and dry to obtain 2,5-bis(1-(furan-2-yl)ethyl)furan. 1 HNMR (500MHz, DMSO-d6) δ7.31 (m, 2H), 6.27 (dd, J=3.1Hz, J=1.9Hz, 2H), 6.00 (d, J=3.1Hz, 2H), 5.93 (s, 2H), 4.16 (q, J=7.2Hz, 2H), 1.56 (d, J=7.2Hz, 6H).

[0066] Table 1. Catalyst and polymer performance in Examples 1-6 and Comparative Examples 1-2

[0067]

[0068] Of course, the present invention may have other various embodiments. Without departing from the spirit and essence of the present invention, those skilled in the art can make various corresponding changes and modifications according to the present invention, but these corresponding changes and modifications should all fall within the protection scope of the claims of the present invention.

Claims

1. An internal electron donor for olefin polymerization, characterized in that, It has the following structure: Among them, R1 and R2 may be the same or different, and each is independently selected from C2 to C3. 20 Straight-chain or branched alkyl groups, C3-C4 20 cycloalkyl, C6-C 20 aryl, C7~C 20 Aryl alkyl group; R3 and R4 may be the same or different, and each is independently selected from hydrogen atoms, C1 to C4. 20 Straight-chain or branched alkyl groups, C3-C4 20 cycloalkyl, C6-C 20 aryl, C7~C 20 Aryl groups.

2. The internal electron donor for olefin polymerization according to claim 1, characterized in that, R1 and R2 may be the same or different, and each is independently selected from C2 to C3. 10 Straight-chain or branched alkyl groups, C3-C4 12 cycloalkyl, C6-C 10 aryl, C7~C 10 Aryl alkyl group; R3 and R4 are the same, selected from hydrogen atoms, C1 to C2. 10 Straight-chain or branched alkyl groups, C3-C4 12 cycloalkyl, C6-C 10 aryl, C7~C 10 Aryl groups.

3. The internal electron donor for olefin polymerization according to claim 1 or 2, characterized in that, The internal electron donor is selected from 3,4-diethoxytetrahydrofuran, 3,4-di-n-propoxytetrahydrofuran, 3,4-diisopropoxytetrahydrofuran, 3,4-di-n-butoxytetrahydrofuran, 3,4-diisobutoxytetrahydrofuran, 3,4-di-n-pentoxytetrahydrofuran, 3,4-dicyclopentoxytetrahydrofuran, 3,4-di-n-hexyloxytetrahydrofuran, 3,4-dicyclohexyloxytetrahydrofuran, 3,4-diphenoxytetrahydrofuran, 3,4-bis(p-tolyloxy)tetrahydrofuran, 3,4-bis(m-tolyloxy)tetrahydrofuran, 3,4-bis(o-tolyloxy)tetrahydrofuran, 2-methyl-3,4-diethoxytetrahydrofuran, 2-methyl-3,4-di-n-propoxytetrahydrofuran, 2-methyl-3,4-diisopropoxytetrahydrofuran. Hydrogenated furan, 2-methyl-3,4-di-n-butoxytetrahydrofuran, 2-methyl-3,4-diisobutoxytetrahydrofuran, 2-methyl-3,4-di-n-pentoxytetrahydrofuran, 2-methyl-3,4-dicyclopentoxytetrahydrofuran, 2-methyl-3,4-di-n-hexyloxytetrahydrofuran, 2-methyl-3,4-dicyclohexyloxytetrahydrofuran, 2-methyl-3,4-diphenoxytetrahydrofuran, 2-methyl-3,4-bis(p-tolyloxy)tetrahydrofuran, 2-methyl-3,4-bis(m-tolyloxy)tetrahydrofuran, 2-methyl-3,4-bis(o-tolyloxy)tetrahydrofuran, 2-ethyl-3,4-diethoxytetrahydrofuran, 2-ethyl-3,4-di-n-propoxytetrahydrofuran, 2-ethyl-3,4-diisobutoxytetrahydrofuran Propoxytetrahydrofuran, 2-ethyl-3,4-di-n-butoxytetrahydrofuran, 2-ethyl-3,4-diisobutoxytetrahydrofuran, 2-ethyl-3,4-di-n-pentoxytetrahydrofuran, 2-ethyl-3,4-dicyclopentoxytetrahydrofuran, 2-ethyl-3,4-di-n-hexyloxytetrahydrofuran, 2-ethyl-3,4-dicyclohexyloxytetrahydrofuran, 2-ethyl-3,4-diphenoxytetrahydrofuran, 2-ethyl-3,4-bis(p-tolyloxy)tetrahydrofuran, 2-ethyl-3,4-bis(m-tolyloxy)tetrahydrofuran, 2-ethyl-3,4-bis(o-tolyloxy)tetrahydrofuran, 2-isopropyl-3,4-diethoxytetrahydrofuran, 2-isopropyl-3,4-di-n-propoxytetrahydrofuran, 2-isopropyl -3,4-Diisopropoxytetrahydrofuran, 2-Isopropyl-3,4-Di-n-Butoxytetrahydrofuran, 2-Isopropyl-3,4-Diisobutoxytetrahydrofuran, 2-Isopropyl-3,4-Di-n-Pentoxytetrahydrofuran, 2-Isopropyl-3,4-Dicyclopentoxytetrahydrofuran, 2-Isopropyl-3,4-Di-n-Hexoxytetrahydrofuran, 2-Isopropyl-3,4-Dicyclohexyloxytetrahydrofuran, 2-Isopropyl-3,4-Diphenoxytetrahydrofuran, 2-Isopropyl-3,4-Bis(p-Tolyloxy)tetrahydrofuran, 2-Isopropyl-3,4-Bis(m-Tolyloxy)tetrahydrofuran, 2-Isopropyl-3,4-Bis(o-Tolyloxy)tetrahydrofuran, 2-n-Butyl-3,4-Diethoxytetrahydrofuran, 2-n-Butyl-3...4-Di-n-propoxytetrahydrofuran, 2-n-butyl-3,4-diisopropoxytetrahydrofuran, 2-n-butyl-3,4-di-n-butoxytetrahydrofuran, 2-n-butyl-3,4-diisobutoxytetrahydrofuran, 2-n-butyl-3,4-di-n-pentoxytetrahydrofuran, 2-n-butyl-3,4-dicyclopentoxytetrahydrofuran, 2-n-butyl-3,4-di-hexyloxytetrahydrofuran, 2-n-butyl-3,4-dicyclohexyloxytetrahydrofuran, 2-n-butyl-3,4-diphenoxytetrahydrofuran, 2-n-butyl-3,4-bis(p-tolyloxy)tetrahydrofuran, 2-n-butyl-3,4-bis(m-tolyloxy)tetrahydrofuran, 2-n-butyl-3,4-bis(o-tolyloxy)tetrahydrofuran, 2-phenyl-3,4 -Diethoxytetrahydrofuran, 2-phenyl-3,4-di-n-propoxytetrahydrofuran, 2-phenyl-3,4-diisopropoxytetrahydrofuran, 2-phenyl-3,4-di-n-butoxytetrahydrofuran, 2-phenyl-3,4-diisobutoxytetrahydrofuran, 2-phenyl-3,4-di-n-pentoxytetrahydrofuran, 2-phenyl-3,4-dicyclopentoxytetrahydrofuran, 2-phenyl-3,4-di-n-hexyloxytetrahydrofuran, 2-phenyl-3,4-dicyclohexyloxytetrahydrofuran, 2-phenyl-3,4-diphenoxytetrahydrofuran, 2-phenyl-3,4-bis(p-tolyloxy)tetrahydrofuran, 2-phenyl-3,4-bis(m-tolyloxy)tetrahydrofuran, 2-phenyl-3,4-bis(o-tolyloxy)tetrahydrofuran, 2,5- -Dimethyl-3,4-diethoxytetrahydrofuran, 2,5-dimethyl-3,4-di-n-propoxytetrahydrofuran, 2,5-dimethyl-3,4-diisopropoxytetrahydrofuran, 2,5-dimethyl-3,4-di-n-butoxytetrahydrofuran, 2,5-dimethyl-3,4-diisobutoxytetrahydrofuran, 2,5-dimethyl-3,4-di-n-pentoxytetrahydrofuran, 2,5-dimethyl-3,4-dicyclopentoxytetrahydrofuran, 2,5-dimethyl-3,4-di-hexyloxytetrahydrofuran, 2,5-dimethyl-3,4-dicyclohexyloxytetrahydrofuran, 2,5-dimethyl-3,4-diphenoxytetrahydrofuran, 2,5-dimethyl-3,4-bis(p-tolyloxy)tetrahydrofuran, 2,5-dimethyl- 3,4-bis(m-tolyloxy)tetrahydrofuran, 2,5-dimethyl-3,4-bis(o-tolyloxy)tetrahydrofuran, 2,5-diethyl-3,4-diethoxytetrahydrofuran, 2,5-diethyl-3,4-di-n-propoxytetrahydrofuran, 2,5-diethyl-3,4-diisopropoxytetrahydrofuran, 2,5-diethyl-3,4-di-n-butoxytetrahydrofuran, 2,5-diethyl-3,4-diisobutoxytetrahydrofuran, 2,5-diethyl-3,4-di-n-pentoxytetrahydrofuran, 2,5-diethyl-3,4-dicyclopentoxytetrahydrofuran, 2,5-diethyl-3,4-di-n-hexyloxytetrahydrofuran, 2,5-diethyl-3,4-dicyclohexyloxytetrahydrofuran, 2,5-diethyl-3,4-dicyclohexyloxytetrahydrofuran, 2,5-diethyl-3,4-Diphenoxytetrahydrofuran, 2,5-Diethyl-3,4-bis(p-tolyloxy)tetrahydrofuran, 2,5-Diethyl-3,4-bis(m-tolyloxy)tetrahydrofuran, 2,5-Diethyl-3,4-bis(o-tolyloxy)tetrahydrofuran, 2,5-Diisopropyl-3,4-diethoxytetrahydrofuran, 2,5-Diisopropyl-3,4-di-n-propoxytetrahydrofuran, 2,5-Diisopropyl-3,4-diisopropoxytetrahydrofuran, 2,5-Diisopropyl-3,4-di-n-butoxytetrahydrofuran Hydrogenated furan, 2,5-diisopropyl-3,4-diisobutoxytetrahydrofuran, 2,5-diisopropyl-3,4-di-n-pentoxytetrahydrofuran, 2,5-diisopropyl-3,4-dicyclopentoxytetrahydrofuran, 2,5-diisopropyl-3,4-di-n-hexyloxytetrahydrofuran, 2,5-diisopropyl-3,4-dicyclohexyloxytetrahydrofuran, 2,5-diisopropyl-3,4-diphenoxytetrahydrofuran, 2,5-diisopropyl-3,4-bis(p-tolyloxy)tetrahydrofuran, 2,5-diisopropyl-3,4-diphenoxytetrahydrofuran propyl-3,4-bis(m-tolyloxy)tetrahydrofuran, 2,5-diisopropyl-3,4-bis(o-tolyloxy)tetrahydrofuran, 2,5-diphenyl-3,4-diethoxytetrahydrofuran, 2,5-diphenyl-3,4-di-n-propoxytetrahydrofuran, 2,5-diphenyl-3,4-diisopropoxytetrahydrofuran, 2,5-diphenyl-3,4-di-n-butoxytetrahydrofuran, 2,5-diphenyl-3,4-diisobutoxytetrahydrofuran, 2,5-diphenyl-3,4-di-n-pentoxytetrahydrofuran One or more of the following: hydrofuran, 2,5-diphenyl-3,4-dicyclopentoxytetrahydrofuran, 2,5-diphenyl-3,4-di-n-hexyloxytetrahydrofuran, 2,5-diphenyl-3,4-dicyclohexyloxytetrahydrofuran, 2,5-diphenyl-3,4-diphenoxytetrahydrofuran, 2,5-diphenyl-3,4-bis(p-tolyloxy)tetrahydrofuran, 2,5-diphenyl-3,4-bis(m-tolyloxy)tetrahydrofuran, and 2,5-diphenyl-3,4-bis(o-tolyloxy)tetrahydrofuran.

4. A main catalyst component for olefin polymerization, characterized in that, Includes the internal electron donor as described in any one of claims 1 to 3, Mg, Ti, and Cl.

5. The olefin polymerization main catalyst component according to claim 4, characterized in that, The main catalyst component contains 1–15 wt% internal electron donor, 12–25 wt% Mg, 1–15 wt% Ti, and 45–60 wt% Cl.

6. An olefin polymerization catalyst, characterized in that, It includes the main catalyst component, co-catalyst, and external electron donor as described in claim 4 or 5.

7. The olefin polymerization catalyst according to claim 6, characterized in that, The co-catalyst is an aluminum-containing compound, and the external electron donor is a silicon-containing compound. The main catalyst component is calculated based on Ti, the co-catalyst is calculated based on Al, and the external electron donor is calculated based on Si. The molar ratio of the main catalyst component, the co-catalyst, and the external electron donor is 1:100-1000:100-500.

8. The olefin polymerization catalyst according to claim 6, characterized in that, The co-catalyst is selected from one or more of trimethylaluminum, triethylaluminum, and triisobutylaluminum.

9. The olefin polymerization catalyst according to claim 6, characterized in that, The external electron donor is selected from one or more of methylcyclohexyldimethoxysilane, dicyclopentyldimethoxysilane, diisopropyldimethoxysilane, and diphenyldimethoxysilane.

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